问题
Do you think necessary to do a bird count ?Yes , we must count them at least once a year
A:it
B:that
C:we
D:they
B:that
C:we
D:they
正确答案是：
同类题型
We should never ________till tomorrow what we can do today .
Mr. Green _______ to Beijing two weeks ago. He ______ there many times.
Who would you like to see you off at the airport?— ______________. Just say “goodbye” at home.
I feel so tired, because there is________ homework to do and it’s ________hot today.